Compasses



C. F. DIECKMANN.

COMPASSES.

Patented June 15, 1920.

APPLICATION FILED JUNE H, "H9.

2 SHEETS-SHEET I.

- WHHMW [7206722571 Ca/rZ f D ta/ mm C. F. DIECKMANN.

COMPASSES.-

APPLICATION FHED JUNE 1|, I919.

1,343,664, Patented June 15, 1920.

2 SHEETS-SHEET 2- UNITED sra'rgs PATENT OFFICE.

CARL F. DIECKMANN, OF CHICAGO, ILLINOIS, ASSIGNOR T0 EUGENE DIETZGENCOMPANY, FACTORY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

COMPAS SES.

Specification of Letters Patent. Pate t d J 15 1920.

Application filed June 11, 1919. Serial No. 303,271.

To all whom it may concern:

Be it known that I, CARL F. DinoK aANN, a citizen of the United States,residing at Chicago, in the county of Cook and State oi Illino1s haveinvented a certain new and useful improvement in Compasses, of which thefollowing is a specification. D

My invention relates to compasses, dividers and like instruments and theobject is to provide a compass having a self centering handle and soconstructed that the device readily lends itself to quantity production.Another object is to provide a device of this character in which thehandle may move out of center in case it forcibly collides with someexternal object, but will offer considerable resistance to suchaccidental displacement. If the head of a co npass is rigidly held incentral position with respect to the two legs, it is apt to become bentor broken in case 1t is dropped or subjected to rough usa e. It isadvantageous, therefore, to make t e handle yieldable, but as a resultof my invention it is able to offer considerable resistance todisplacement, the resistance being limited =sufiiciently, however, toprevent breakage or distortion of the parts.

I accom lish my objects by the mechanism illustrate in the accompanyingdrawings in which Figure 1 is a side view of an instrument embodying theinvention, the lower portion of the legs being broken away.

Fig. 2 is a sectional view on the line 2--2-, Fig. 1.

Fig. 3 is a detail view showlng the centering plate, the conical rollersand associated parts.

Fig. 4 is a perspective view showing the inner face of the shank of oneof the legs.

Fig. 5 is a face view of the centering plate. l

Fig. 6 is a sectional view on the line 6( 5, Fig. 5, this View showingthe rollers in posltion.

Fig. 7 is a view of one of the shanks. Fig]. 8 is a sectional view onthe line 8-8, l

l iike numerals denote like parts through the several views. A

In the type selected to illustrate the invention, the head comprises ahandle 1 haying two depending arms a, 2. A pivot p n 3 is adapted topass through care of said arms and screw into the opposite one as bestshown in Fig. 2. A pin 4 is fastened at the lower end of the arms insuch position as to pass between the branches 5, 5 of the lower end ofthe centering plate 6.

The two legs 7, 7 have shanks 8, 8 with recesses 9 formed in their innerfaces for receiving the conical rollers 10. The rollers are arrangedradially with their smaller ends toward the center. The centering platehas an aperture 11 for each of the rollers, the apertures being arrangedequidistantly and practically conforming to the outline of the rollers.

The shanks 8 are countersunk on the outer faces to receive two washers15, 1G. The washer 15 is in the form of a segment of a sphere, the flatbase resting upon the inner surface of one of the arms 2 and thespherical crown fitting into the countersink in the adjacent shank. Thewasher is thick enough to maintain a space between the inside of the armand the outside of the shank. The washer 16 is in the form of a plainring which, however, is thick enough to maintain a space between theshank in which it is countersunk and the adjacent surface of the arm 2.Both of the washers encircle the pin 3, but the washer 16 has aninternal diameter which is appreciably larger than the diameter of thepin, while the internal diameter of washer 15 is such as to make aturning fit with the )in. The consequence is that the washer 16 is freeto move slightly in a plane transverse to the pin. hen such movementoccurs, the opposite shank will articulate upon the washer 15 after themanner of a ball and socket joint.

In operation, when the legs 7, 7, are swung toward each other or awayfrom each other they will cause the rollers 10 to roll about theirlongitudinal axes, said axes naturally remaining stationary and hencecausing the rollers to hold the centering plate stationary. As thecentcrin plate engages the in 4, which is rigi with the handle, itollows that the handle 1 will remain stationary, 2'. 6., centered withrespect to the two le s. As a result of the slant of the bottom 0 therecesses 9, the rollers 10 have a constant tendency to move radiallyoutward which causes their outer ends to bear against and frictionallyengage the outer rims of the recesses 9.

This generates, altogether, a large amount of friction. In the case ofball bearings a hall cannot, theoretically, bear at more than one or twopoints on a given member at a given time, but with my construction, therollers make line contact with one slope of the recess in the shank andsurface contact with the other slope (or the rim) of. the groove, wherethe end of the roller engages it. Consequently, the amount of frictionproduced is very much greater than it is with a ball bearing and yet theamount of friction may be confined within proper limits by suitablyadjusting the screw pin 3. This construction also produces very durableinstrument because the wear is distributed over the entire side, andupon the end of the roller. By thus distributing the wear over a muchlarger area than is obtainable in a ball bearing, the life of the deviceis greatly prolonged and adjustment is required only at long intervals.Ely construction has another advantage in that it lends itself toquantity production. It will be noted that the apertures ll in thecentering plate are somewhat longer than the rollers and thus afford therollers a certain freedom of movement in a radial direction. Hence, ifthe recesses 9 should not be perfectly accurate, the parts may adjustthemselves, especially in view of the ball and socket connection betweenone of the arms 2 and the adjacent shank.

It will be understood by those skilled in the manufacture of devices ofthis class that very slight inaccuracies of manufacture will, in anordinary instrument, produce a. more or less inferior article. Toproduce great accuracy, however, requires skilled and patient workmenand entails considerable time and expense. It is a great advantage,therefore, to obtain a construction such as mine which enables themanufacturer to produce a smooth acting, long wearing, and accurateinstrument by methods which utilize to an unusual extent jigs, dies, andsimilar labor saving devices.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent, is:

1. A device of the class described, having a head, conical rollers, legshaving shanks with annular recesses sunk in their inner faces toaccommodate said rollers, and a con tering plate interposed between saidshanks and having apertures to accommodate said rollers, said centeringplate being connected to the head for holding it in central posi tion.

2. A device of the class described, having a head comprisinc a handleand two depend ing arms, conical rollers, legs having shanks withannular recesses sunk in their inner faces to accommodate said rollersand a centering plate interposed between the shanks and having aperturesto accommodate said rollers and be held in central position lrv them,said rollers being adapted to make end contact with the outer rims ofsaid recesses.

A device of the class described having a head comprising a handle andtwo depending arms, conical rollers, legs having shanks with annularrecesses sunk in their inner faces to accommodate said rollers, acentering plate interposed between said shanks and having apertures toaccommodate said rollers, the edges of the apertures being fairly closeto the sides of the rollers whereby the rollers keep the plate centered,said plate being connected to the head for holding it in centralposition, said rollers being adapted to make end contact with the outerrim of the annular recesses.

4. A compass having a head comprising a handle and two depending arms,two legs having shanks with concentric recesses sunk in their innerfaces, said recesses having sloping sides, conical rollers the sides ofwhich make line contact with one slope of the recesses and the ends makesurface contact with the remaining slope of the recesses, and acentering plate interposed between said shanks and having apertures thesides of which are adapted to engage the sides of the rollers forholding the plate centered, the plate being connected to the head forholding the handle centered.

A compass having a head comprising a handle and two depending arms, twolegs having shanks with concentric recesses sunk in their inner faces,said recesses having at least one sloping wall, conical rollers thesides of which make line contact with the sloping wall of the recessesand the ends make surface contact with the remaining wall of therecesses, a centering plate interposed bc 0 tween said shanks and havingapertures the sides of which are adapted to engage the sides of therollers for holding the plate centered, the plate being connected to thehead for holding the handle centered, and a pivot pin mounted in the twodepending arms, said pin making a turning fit with the centering plate.

6. A device of the class described having a head comprising a handle andtwo depending arms, two legs having shanks with concentric recessesformed in their inner faces, the recesses having sloping sides,truncated conical rollers rolling in said recesses and making linecontact with one slope of the recesses and end contact with the otherslope, the shanks having sockets in their outer faces, washers seatingin said sockets and protruding from the outer surfaces of the shanks,and means for drawing the arms into contact with the protruding ends ofthe washers for holding the parts centered.

7. A device of the class described having a head comprising a handle andtwo depending arms, two legs having shanks with concentric recessesformed in their inner faces, said recesses having sloping sidestruncated conical rollers rolling in said rccesses and making linecontact with one slope of the recess and end contact with the otherslope a centering plate interposed between said shanks and havingapertures adapted to accommodate said rollers, the shanks having socketsin their outer faces, washers seating in said sockets and protrudingfrom the outer surfaces of the shanks, and means for drawing the armsinto contact with the protruding ends of the washers for holding theparts centered. 7

S. A device of the class described having a head comprising a handle andtwo depending arms, two legs having shanks with concentric recessesformed in their inner faces, at least one side of said recesses beingsloping, truncated conical rollers rolling in said recesses and makingline contact with one side of the recess and end contact with the otherside, the shanks having sockcts in their outer faces, washers seating insaid sockets and protruding from the outer surfaces of the shanks, and ascrew pin for drawing the arms into contact with the protruding ends ofthe washers for holding the parts centered, one of said washers being inthe shape of a segment of a sphere. and the socket in the shank whichreceives it being spherically concave to fit over the spherical portionof the washer, and the opposite washer having an enlarged internaldiameter so that it may move slightly transversely to said pin.

In witness whereof, I have hereunto subscribed my name.

CARL F. DIECKMANN.

